Micronisation means

ABSTRACT

An apparatus ( 10 ) for micronizing an inorganic salt, having a receiving vessel ( 14 ) for receiving the salt ( 46 ) to be micronized in an interior of the receiving vessel ( 14 ); a grinding unit ( 22 ) for comminuting the salt ( 46 ) to be micronized located in the receiving vessel ( 14 ) and for forming micronized salt particles ( 54 ); an ascending pipe ( 24 ), which is connected fluidically to the receiving vessel ( 14 ) and serves to transport the micronized salt particles ( 54 ), wherein one end of the ascending pipe ( 24 ) has an outlet orifice ( 38 ) through which the micronized salt particles ( 54 ) can flow out of the apparatus ( 10 ); a fan ( 26 ) for generating an air stream ( 40 ); and a housing ( 12 ) with an air outlet ( 44 ) and an air duct ( 42 ) connecting the fan ( 26 ) to the air outlet ( 44 ), wherein the air duct ( 42 ) is separated by at least one wall from the interior of the receiving vessel ( 14 ), such that the air stream ( 40 ) generated by the fan ( 26 ) does not flow through the interior of the receiving vessel ( 14 ), and wherein the air outlet ( 44 ) at least partly surrounds the ascending pipe ( 24 ) in a region of the outlet orifice ( 38 ).

The present invention relates to an apparatus for micronizing aninorganic salt. Such an apparatus is often also known as a micronizerand serves to produce salt particles in the micrometer and submicrometerrange to produce airborne salt particulates or a salt aerosol.

Such micronizers are conventionally used in salt caves, where the saltaerosol can be inhaled. This may be done for medical or cosmeticpurposes, but also purely for wellness purposes. Micronizers are alsoincreasingly used in saunas or other wellness facilities for theabove-stated purposes.

To be effective as an aerosol in such facilities, the salt particlespresent in the aerosol should have an average particle diameter ofaround 2 μm, preferably of less than 2 μm, such that they can penetrateas deep as possible into the pulmonary airways.

Various technologies already exist for producing micronized saltparticles with average particle diameters within the above-stated valuerange.

For example, DE 10 2004 059 530 A1 describes an apparatus for producinga salt aerosol, in which the grinding process is performed by a rapidlyrotating grinding tool. The apparatus described in this document has thedisadvantage, however, that grinding is here performed using amechanical grinding apparatus, which is disadvantageous on the one handin terms of wear to the grinding apparatus and also the introduction ofimpurities, whether from the grinding tool or from lubricants from thedrive. It has furthermore also been demonstrated that such apparatusesdisplay only limited suitability for continuous operation due to therelatively frequent maintenance intervals, attributable inter alia alsoto the use of corrosive common salt. Finally, these apparatuses alsohave the disadvantage of being relatively noisy, such that such anapparatus tends to be perceived as troublesome when used in a wellnessfacility.

U.S. Pat. No. 5,747,002 describes an apparatus for producing a saltaerosol using a jet mill principle. In this apparatus, grinding isperformed according to the countercurrent principle, followed bycyclone-based classification. Although jet mills do not in general havesome of the above-described disadvantages, the apparatus disclosed inU.S. Pat. No. 5,747,002 A does have the disadvantage on the one handthat the design thereof is relatively complex and on the other hand thatgases are used therein under high pressure, which leads to high energyconsumption and to a safety risk. In addition, this apparatus alsoenables the production only of particles with a diameter of around 7 μm.

EP 2 457 559 A1 describes a further apparatus for producing a saltaerosol. The salt to be micronized is in this case present in aretaining stage and is subjected to a grinding process. A separatingstage is arranged with the retaining stage, the grinding stage and a gassupply upstream of the retaining stage in such a way that the gas flowsthrough the grinding apparatus along the longitudinal axis thereof. Theselected design of this apparatus makes it difficult, however, to ensurea more or less uniform particle size of the salt particles contained inthe salt aerosol produced. To prevent undesirably large salt particlesfrom flowing out of the apparatus, screens or baffle plates have herespecially to be used.

It is thus an object of the present invention to provide an apparatusfor micronizing an inorganic salt and for producing a salt aerosol whichovercomes the above-stated disadvantages. It is here in particular anobject of the present invention to improve such an apparatus in terms ofthe reliability with which salt particles present in the salt aerosolcan be produced with maximally uniform particle sizes and in terms ofcleanability, hygiene, noise emission, maintenance intensity andmanufacturing costs.

This object is achieved by an apparatus as claimed in claim 1, whereinthis apparatus comprises the following:

a receiving vessel for receiving the salt to be micronized in aninterior of the receiving vessel;

a grinding unit for comminuting the salt to be micronized located in thereceiving vessel and for forming micronized salt particles;

an ascending pipe, which is connected fluidically to the receivingvessel and serves to transport the micronized salt particles, whereinone end of the ascending pipe has an outlet orifice through which themicronized salt particles can flow out of the apparatus;

-   -   a fan for generating an air stream; and

a housing with an air outlet and an air duct connecting the fan to theair outlet, wherein the air duct is separated by at least one wall fromthe interior of the receiving vessel, such that the air stream generatedby the fan does not flow through the interior of the receiving vessel,and wherein the air outlet at least partly surrounds the ascending pipein a region of the outlet orifice.

The apparatus according to the invention is distinguished in particularby the novel manner of air conduction within the housing compared withthe prior art. That is to say, the receiving vessel, into which the saltto be micronized is conventionally introduced before the apparatus isstarted up, is not flowed through directly by the air stream generatedby the fan, as is generally the case with such apparatuses. Instead, anair duct is provided in the housing which is separated from the interiorof the receiving vessel by at least one wall. This air duct leads withinthe housing of the apparatus from the fan to an air outlet. The airoutlet at least partly surrounds an ascending pipe, which is connectedto the receiving vessel and in which the micronized salt particlescomminuted by the grinding unit ascend. More precisely, the air outletsurrounds the ascending pipe in the region of the outlet orifice throughwhich the micronized salt particles flow out of the apparatus. The airstream generated by the fan and the micronized salt particles are thusbrought together in the region of the outlet orifice arranged at theupper end of the ascending pipe.

The above-mentioned arrangement of the air duct and the avoidance ofdirect flow through the receiving vessel result in the followingadvantages: on the one hand a suction effect is produced in the interiorof the ascending pipe by the flow around the outlet orifice, whichsuction effect preferably only becomes effective in the upper part ofthe ascending pipe, i.e. in the vicinity of the outlet orifice. Thistype of suction flow, which is induced in the upper part of theascending pipe, acts only on the salt particles which have already beensufficiently comminuted in the grinding unit and have ascended, due tothe acceleration thereof contrary to gravity experienced within thegrinding unit, to a given height in the interior of the receiving vesseland of the adjoining ascending pipe. This in turn ensures thatundesirably large salt particles are not caught up at all by theabove-mentioned suction flow and thus also do not flow out of theapparatus, since these relatively large salt particles do not ascend farenough in the receiving vessel and the adjoining ascending pipe due totheir relatively heavier weight. To conclude, compliance with a maximumparticle size for the outflowing salt particles may thus be guaranteed.

The type of air conduction according to the invention within theapparatus has the additional advantage that the salt located in theapparatus is shielded in a way from the fan, since the air stream isconveyed separately from the salt particles within the apparatus in themanner of a bypass. This is in turn associated with hygiene-relatedadvantages and also has a positive effect in terms of maintenanceintensity due to a lower susceptibility to corrosion.

A further advantage of the apparatus according to the invention lies inits comparatively inexpensive manufacture and the comparatively simplecleanability of the apparatus, since for example, compared with theapparatus known from EP 2 457 559 A1, no screens or baffle plates haveto be specially provided in the ascending pipe.

According to a refinement of the present invention, the air outlet ofthe air duct is arranged concentrically with the outlet orifice of theascending pipe, wherein the air outlet completely surrounds the outletorifice.

This refinement has the advantage that the above-described suction flow,which is induced in the upper region of the ascending pipe, takes effectover the entire diameter of the ascending pipe. This leads to relativelygood distribution of the micronized salt particles flowing out of theapparatus. In addition, the intensity with which the micronized saltparticles flow out of the apparatus may also be relatively wellregulated by the above-mentioned principle.

According to a further refinement of the present invention, the grindingunit comprises (i) a motor, (ii) a magnet driven rotationally by themotor and (iii) a ball of magnetizable material, wherein the ball isarranged within the receiving vessel and the motor and the magnet driventhereby are arranged outside the receiving vessel, and wherein the ballis moved relative to the receiving vessel by the rotation of the magnet.In this respect, it is particularly preferable for the grinding unit tocomprise precisely one ball of magnetizable material.

This refinement has the advantage that contactless drive of the grindingunit is ensured thereby, “contactless” here being understood to meanthat there is no direct, mechanical contact between the ball located inthe receiving vessel and the drive with motor and magnet connectedthereto conventionally arranged beneath the receiving vessel. This is inturn advantageous for reasons of hygiene, since the salt located in thereceiving vessel cannot be contaminated by lubricating greases or oilsto be found in the region of the drive. Moreover, the risk of corrosionof the drive parts of the grinding unit may also be enormously reduced.It has additionally been found to be advantageous that this type ofgrinding unit with magnetically driven ball is relatively quiet comparedwith other grinding apparatuses known in the art.

When a grinding unit with magnetically driven ball is used as stated, aplurality of effects work towards comminution of the salt to bemicronized or formation of the micronized salt particles: on the onehand, the salt grains are set in motion by the ball rotating in thereceiving vessel, whereby they bump into one another and also into theinternal wall of the receiving vessel. The salt grains thereby crush andpulverize one another. To a lesser extent, the salt grains are alsoground between the ball and the internal wall of the receiving vessel.

According to one preferred refinement, the receiving vessel has aclosed, round bottom face.

This guarantees that the ball may move over a circular path atrelatively high speeds. Due to the centrifugal force acting on the ballduring rotational drive of the ball, the latter conventionally movesalong the outer edge of the bottom face with support from the internalwalls of the receiving vessel.

According to a further refinement, provision is made for the diameter ofthe bottom face to correspond to at least 5 times, preferably at least10 times the diameter of the ball.

The ball is thus preferably selected to be very small in comparison withthe diameter of the receiving vessel. The receiving vessel itself ispreferably cylindrical in shape. A conical shape would however likewisebe feasible for the receiving vessel.

According to a further refinement, the motor has a motor shaft on whichthe magnet is arranged eccentrically, wherein the grinding unitadditionally has a counterweight which corresponds approximately to theweight of the magnet, i.e. to between 90% and 110% of the weight of themagnet, and is arranged eccentrically on the motor shaft on an oppositeside from the magnet.

This refinement has the advantage of preventing drive imbalances andthus ensuring higher speeds. The noise caused by the drive may therebylikewise also be minimized. It goes without saying, in any event, thatthe overall mechanical stability of the drive is also improved thereby.

The apparatus according to the invention furthermore preferablycomprises a control unit for controlling the motor, wherein the controlunit is designed to operate the motor at a first nominal speed, whereinthe first nominal speed is selected to be between 1,500 and 2,500revolutions per minute.

It should be noted that the term “first nominal speed” is used heremerely to distinguish it from a “second nominal speed” explained ingreater detail below. This terminology is not intended, however, toimply any order, priority or other meaning.

A nominal speed of 1,800 to 2,800 revolutions per minute has proven tobe particularly preferred. It has been found that in this speed range anoptimum comminution effect is achieved for the salt crystals located inthe receiving vessel.

According to a further refinement, the control unit is designed tochange the nominal speed of the motor at regular intervals temporarilyto a second nominal speed and then in each case to return to the firstnominal speed, wherein the second nominal speed is greater than thefirst nominal speed.

The magnet driven by the motor is thus temporarily accelerated to agreater extent at regular intervals, preferably to beyond the maximum ofthe above-mentioned speed ranges. The consequence of this is that themagnetic force acting on the ball is no longer sufficient to force theball to rotate jointly with the magnet driven by the motor. The ball cantherefore no longer follow the rotating magnet exactly and is caused toleave its circular path. This may result in a type of wobbling by theball within the receiving vessel. The particular advantage of thisprocedure is that accumulations of salt in the middle of the receivingvessel are carried along by the ball and fed to the comminution process.The subsequent return to the first nominal speed brings the ball back toits circular path within the receiving vessel.

The apparatus preferably has an input device for the user to define thefirst nominal speed. This allows the user to regulate the intensity withwhich the generated salt aerosol flows out of the apparatus. Thequantity of outflowing salt aerosol may thus for example be adapted tothe size of the space in which the apparatus has been set up. The firstnominal speed may conceivably be set via one or more selector switches.

Alternatively or in addition to the latter refinement, the apparatus maycomprise a temperature sensor for generating a temperature signal and ahygrometer for generating a humidity signal, wherein the control unit isdesigned to regulate the first nominal speed as a function of thetemperature signal and of the humidity signal. The control unit ispreferably designed to switch off the motor if a predefined temperatureand/or humidity threshold value is exceeded. This serves in particularto prevent damage and malfunctions.

The advantage of this refinement is that the intensity of the saltaerosol flowing out of the apparatus is regulated automatically. This isadvantageous in particular because the ambient climate is critical forthe properties of the salt aerosol. Too damp an indoor climate preventsthe apparatus according to the invention from functioning properly. Toohot an ambient climate may result in damage to various electrical andmechanical parts of the apparatus. To avoid malfunctioning or damage,provision may therefore be made for the control unit to be designed toswitch off the apparatus if a temperature and/or humidity thresholdvalue is reached.

According to a further refinement of the present invention, theascending pipe is preferably curved.

The curvature of the ascending pipe in particular offers the possibilityof a space-saving arrangement, without having to reduce the effectivelength of the ascending pipe. With a 90° curvature of the ascendingpipe, the lower part of the ascending pipe connected to the receivingvessel may be vertically oriented, wherein the micronized salt particlesexiting the apparatus exit horizontally from the outlet orifice arrangedat the upper end of the ascending pipe.

According to a further refinement, the receiving vessel is arrangeddetachably on the housing.

To fill the receiving vessel with salt, the latter may thus be separatedfrom the housing. This also makes it easier to clean the receivingvessel.

According to a further refinement of the present invention, provision isfurthermore made for the apparatus to comprise lighting for illuminatingthe interior of the receiving vessel and/or for illuminating the outletorifice.

The advantage of illuminating the interior of the receiving vessel isthat the filling level of the salt located in the receiving vessel maybe readily seen by the user. By illuminating the outlet orifice, themicronized salt particles exiting from the apparatus may be betterobserved.

It goes without saying that the above-mentioned features and those stillto be explained below may be used not only in the respectively statedcombination but also in other combinations or alone, without goingbeyond the scope of the present invention.

One exemplary embodiment of the invention is explained in greater detailin the following description and illustrated in the drawings, in which:

FIG. 1 is a perspective view of an exemplary embodiment of the apparatusaccording to the invention;

FIG. 2 is a further perspective view of the exemplary embodiment shownin FIG. 1 of the apparatus according to the invention, wherein, incomparison with FIG. 1, a receiving vessel belonging to the apparatushas been detached from the housing of the apparatus;

FIG. 3 is a plan view from the front of the exemplary embodiment shownin FIG. 1 of the apparatus according to the invention;

FIG. 4 is a cross-sectional view of the exemplary embodiment shown inFIG. 1 of the apparatus according to the invention;

FIG. 5 is a longitudinal sectional view of the exemplary embodimentshown in FIG. 1 of the apparatus according to the invention; and

FIG. 6 is a perspective internal view of the exemplary embodiment shownin FIG. 1 of the apparatus according to the invention, wherein thehousing is hidden or only shown schematically.

FIGS. 1-6 show different views of an exemplary embodiment of theapparatus according to the invention. The apparatus is designatedoverall therein with reference numeral 10.

The apparatus 10 comprises a housing 12 and a receiving vessel 14, whichmay preferably be attached detachably to the housing 12. To this end, acavity or recess 16 is provided on the front of the housing 12 intowhich the receiving vessel 14 may be inserted, preferablyform-fittingly.

The receiving vessel 14 serves to receive grains of salt 46, which areto be micronized using the apparatus 10 to produce a salt aerosol. Thereceiving vessel 14 preferably has a cylindrical shape with a closed,circular bottom face 18. The receiving vessel 14 is preferably open atthe top. The salt particles 54 comminuted in the receiving vessel 14 maythus exit through an orifice 20 at the top of the receiving vessel 14during operation of the apparatus 10.

The apparatus according to the invention 10 further comprises a grindingunit 22, an ascending pipe 24 and a fan 26, which are preferably allarranged within the housing 12 (see FIGS. 4-6).

The grinding unit 22 serves in comminuting the salt 46 to be micronizedand located in the receiving vessel 14, i.e. to form micronized saltparticles 54. In the exemplary embodiment shown here, the grinding unit22 comprises a magnetically driven ball 28, which has been inserteddetachably into the receiving vessel 14. The ball 28 is moved on acircular path within the receiving vessel 14 by means of a rotationallydriven magnet 30 during operation of the apparatus 10. To this end, themagnet 30 is attached eccentrically to a motor shaft 32 of an electricaldrive motor 34. The electric motor 34 is preferably supplied with powervia an energy storage means 36 likewise incorporated in the housing 12,which means for example comprises a storage battery.

The ascending pipe 24 is connected fluidically with the interior of thereceiving vessel 14. It serves to transport the salt particlesmicronized by the grinding unit 22 in the interior of the receivingvessel 14 outwards out of the apparatus 10. When viewed in the directionof flow of the micronized salt particles, the ascending pipe 24 is thusarranged downstream relative to the receiving vessel 14. The lower partof the ascending pipe 24, which is connected to the receiving vessel 14,is preferably arranged coaxially relative to the receiving vessel 14.The upper part of the ascending pipe 24 is preferably curved. Althoughan uncurved ascending pipe could in principle also be considered, acurved ascending pipe has the advantage, compared with an uncurvedascending pipe, of lower structural height for the same effectivelength.

At the end remote from the receiving vessel 14, the ascending pipe 24comprises an outlet orifice 38 through which the micronized saltparticles 54 may flow outwards out of the apparatus 10.

The fan 26, which preferably takes the form of a ventilating fan,generates an air stream inside the housing 12 which is indicatedschematically with arrows 40 (see FIGS. 4 and 5). The fan 26 ispreferably designed to generate a volumetric flow rate in the range from10-20 m3/h. An essential feature of this air stream 40 is that it doesnot, as is generally conventional for such micronizers, flow through thereceiving vessel 14, but rather is conveyed inside the housing 12 pastthe receiving vessel 14 by an air duct 42 not described in any greaterdetail here. The air duct 42 opens at the opposite end from the fan 26into an air outlet 44. This air outlet 44 is preferably arrangedconcentrically with the outlet orifice 38 of the ascending pipe 24. Theair outlet 44 preferably completely surrounds the outlet orifice 38.Both the outlet orifice 38 and the air outlet 44 preferably have a roundouter contour. The concentric arrangement thereof thus results in aroughly circular ring-shaped cross-section for the air outlet 44.

The mode of operation of the apparatus 10 is best understood withreference to FIGS. 4 and 5.

First of all, the salt 46 loaded into the receiving vessel 14 before thestart of operation is comminuted or micronized by means of the grindingunit 22. To this end, the magnet 30 is rotated by means of the electricmotor 34. The motor 34 is in this case controlled by a control unit 48which regulates the nominal speed of the motor preferably to 1,500 to2,500 revolutions per minute. Using selector switches 50, which aremounted on the outside of the housing 12 and in this case generallydesignated input devices, the speed of the motor 34 may be adjustedstepwise by the user. In this way, the current intensity of thegenerated salt aerosol may be adjusted by the user. Continuous speedadjustment, for example by a rotary knob, is in principle alsoconceivable.

The ball 28 located in the receiving vessel 14 is carried along by therotation of the magnet 30, such that the ball rotates approximatelysynchronously with the magnet 30 within the receiving vessel 14. Tocompensate the centrifugal forces arising as a result of movement of themagnet 30, a counterweight 52 is preferably mounted on the motor shaft32 on the opposite side from the magnet 30. Instead of thiscounterweight 52, a second magnet may also be arranged at this position.

The comminution process of the salt crystals 46 caused by movement ofthe ball 28 is based on multiple effects: on the one hand, the saltcrystals 46 are set in motion by the rotation of the ball 28 and tossedaround inside the receiving vessel 14. Some salt crystals thereby impactagainst one another. Others in turn thereby impact against the internalwall of the receiving vessel 14. Still other salt crystals are groundbetween the ball 28 and the internal wall of the receiving vessel 14. Ithas been found that, due to these effects taking place together, thesalt crystal 46 comminution process is very efficient.

The comminuted or micronized salt crystals, which are indicatedschematically in FIGS. 4 and 5 and are provided with reference numeral54, are flung upwards by the movement of the ball 28 inside thereceiving vessel 14. Provided these are sufficiently small, they mayascend in the receiving vessel 14 and within the adjoining ascendingpipe 24 contrary to the effect of the gravitational force. The airstream 40 generated by the fan 26 generates a type of suction flow inthe region of the outlet orifice 38 as a result of the above-describedflow around the ascending pipe 24. This suction flow is induced insidethe ascending pipe 24 in particular in the region of the outlet orifice38. It is thus ensured that only the micronized salt particles 54 whichhave ascended inside the receiving vessel 14 and inside the ascendingpipe 24 against the effect of the gravitational force are caught up bythe suction flow and flow out of the outlet orifice 38 and thus of theapparatus 10. Larger salt particles, on the other hand, which remain onthe bottom of the receiving vessel 14 due to their weight or at least donot ascend as far as into the upper region of the ascending pipe 24, arenot caught up by the suction generated in the ascending pipe 24 by theair stream 40 and thus remain in the apparatus 10.

To prevent larger salt crystals which are not caught up by the rotatingball from settling permanently in the middle of the bottom of thereceiving vessel 14, provision is preferably made for the control unit48 to increase the nominal speed of the motor 34 at regular intervalstemporarily to above a defined threshold value. If namely a given speedof the motor 34 is exceeded, the force acting between the ball 28 andthe magnet 30 is namely no longer sufficient for the ball 28 to be ableto follow the rotation of the magnet 30. The ball 28 then begins to“prance about” on the bottom face 18 of the receiving vessel 14. In theprocess, it moves over regions of the bottom face 18, in particular alsothe middle of the bottom face 18, which it does not otherwise reachduring its conventional rotation along the outer edge of the bottom face18. The salt crystals located at these points are then thus likewisecaught up. The above-stated temporary increase in speed preferably takesplace for just a few seconds.

The following features may also be provided: an indicator 56 may beprovided on the outside of the housing 12 for indicating the storagebattery 36 level. In addition, the apparatus 10 may optionally compriselighting, not shown in the drawings for the sake of simplicity, whichserves to illuminate the outlet orifice 38 and/or the interior of thereceiving vessel 14. Moreover, the apparatus 10 optionally comprises atemperature sensor and a hygrometer, wherein the control unit 48 is inthis case designed to regulate the speed of the motor 34 as a functionof the temperature signal generated by the temperature sensor and/or thehumidity signal generated by the hygrometer. The control unit 48 ispreferably designed to switch off the motor 34 if a predefinedtemperature and/or humidity threshold value is exceeded. This serves inparticular to prevent damage and malfunctions.

1. An apparatus for micronizing an inorganic salt, comprising: areceiving vessel for receiving the inorganic salt to be micronized in aninterior of the receiving vessel; a grinding unit configured tocomminute the inorganic salt to be micronized located in the receivingvessel and to form micronized salt particles; an ascending pipe, whichis connected fluidically to the receiving vessel and serves to transportthe micronized salt particles, wherein at one end of the ascending pipean outlet orifice is arranged through which the micronized saltparticles can flow out of the apparatus; a fan configured to generate anair stream; and a housing with an air outlet and an air duct connectingthe fan to the air outlet, wherein the air duct is separated by at leastone wall from the interior of the receiving vessel, such that the airstream generated by the fan does not flow through the interior of thereceiving vessel, and wherein the air outlet at least partly surroundsthe ascending pipe in a region of the outlet orifice.
 2. The apparatusas claimed in claim 1, wherein the air outlet is arranged concentricallywith the outlet orifice and completely surrounds it.
 3. The apparatus asclaimed in claim 1, wherein the grinding unit comprises a motor, amagnet driven rotationally by the motor, and a ball of magnetizablematerial, wherein the ball is arranged in the receiving vessel, andwherein the motor and the magnet are arranged outside the receivingvessel.
 4. The apparatus as claimed in claim 3, wherein the grindingunit comprises precisely one ball of magnetizable material.
 5. Theapparatus as claimed in claim 3, wherein the receiving vessel has aclosed, round bottom face.
 6. The apparatus as claimed in claim 5,wherein a diameter of the bottom face corresponds to at least 5 times,preferably at least 10 times a diameter of the ball.
 7. The apparatus asclaimed in claim 3, wherein the motor has a motor shaft on which themagnet is eccentrically arranged.
 8. The apparatus as claimed in claim7, wherein the grinding unit has a counterweight which corresponds tobetween 90% and 110% of a weight of the magnet, and is arrangedeccentrically on the motor shaft on an opposite side from the magnet. 9.The apparatus as claimed in claim 3, wherein the apparatus comprises acontrol unit which is configured to control the motor, wherein thecontrol unit is configured to operate the motor at a first nominalspeed, wherein the first nominal speed is selected to be between 1,500and 2,500 revolutions per minute.
 10. The apparatus as claimed in claim9, wherein the control unit is configured to control the motor to changeat regular intervals temporarily from the first nominal speed to asecond nominal speed and then in each case to return to the firstnominal speed, wherein the second nominal speed is greater than thefirst nominal speed.
 11. The apparatus as claimed in claim 9, whereinthe apparatus has an input device for a user to define the first nominalspeed.
 12. The apparatus as claimed in claim 9, wherein the apparatuscomprises a temperature sensor for generating a temperature signal and ahygrometer for generating a humidity signal, wherein the control unit isconfigured to regulate the first nominal speed as a function of thetemperature signal and of the humidity signal.
 13. The apparatus asclaimed in claim 1, wherein the ascending pipe is curved.
 14. Theapparatus as claimed in claim 1, wherein the receiving vessel isarranged detachably on the housing.
 15. The apparatus as claimed inclaim 1, wherein the apparatus comprises lighting configured toilluminate the interior of the receiving vessel and/or to illuminate theoutlet orifice.
 16. The apparatus as claimed in claim 1, wherein theascending pipe comprises a lower end and an opposing upper end, theupper end being the one end at which the outlet orifice is arranged,wherein the lower end of the ascending pipe is connected to thereceiving vessel, and wherein the air outlet at least partly surroundsthe upper end of the ascending pipe in the region of the outlet orifice.